Formerly used as an onomatopoetic expression to describe the sound of laughter in '60s theatrical jargon.

A decade later was used as an expression of distaste, disgust, or revulsion by people who attended comedy clubs, probably due to the disgusting nature of the jokes told in a more vulgarity-tolerant society. Can also be used in its adjective form, yucky.

The Urban Dictionary T-Shirt

1. (v) to vomit, barf, blow chunks, toss out last night's salsa
2. (v) a normal male's response after meatin' the skin taco or shakin' the tree
3. (n) the visible, often messy product of either the above actions

1) I just yucked in the barf bucket in the basement.
2) I pulled out and yucked all over the bed.
3) Get that yuck outta here, I'm tryin' to eat.